Circuit breaker



CIRCUIT BREAKER 2 Sheets-Sheet 1 Filed July 31, 1946 INVENTORS ATTORNEY A mm mm 3 3 w mg w J l- A x w 9 in,

a a we. 9 w 3 a 4 5 7 0 J 3 Z l l r /d/ 3 4 Z z 0 /w 36 7 9 7 m a w 5 June 20, 1950 J. SANDIN EI'AL CIRCUIT BREAKER 2 SheetsSheet 2 Filed July 31, 1946 [baa/02600 3. a M w INVENTORS Jrame Sand/n and 6/ EB? 0rd Hausa/'1 q 2 ATTORNEY Wl TNESSES: 5% 7 Patented June 20, 1950 CIRCUIT BREAKER Jerome Sandin and Richard Hauser, Pittsburgh,

Pa., assignors to Westin ration, East Pittsburgh Pennsylvania ghouse Electric Corpo- Pa., a corporation of Application July 31, 1946, Serial No. 687,478

17 Claims.

This invention relates to circuit interrupters and more particularly, to circuit breakers of the type used for controlling industrial power distribution and secondary network circuits.

One object of the invention is to provide a circuit breaker with a plurality of auxiliary switches which are interchangeably mounted, and which are removable from the breaker without disengaging any connections with the mechanism which operates the switches.

Another object of the invention is to provide a circuit breaker with a plurality of auxiliary switches, one of which is operated only when the breaker is automatically opened, the other switch being operated each time the breaker is opened whether manually or automatically operated,

both of said switches being removable from the breaker without disengaging any connection with the mechanism which operates them.

Another object of the invention is to provide a circuit breaker with an auxiliary switch operated by a torsion spring, one end of which is directly engaged and operated by the main movable contact structure of the circuit breaker.

Another object of the invention is to provide a circuit breaker with a bell alarm switch operated by a torsion spring, one end of which is operated directly by the releasable operating mechanism of the circuit breaker.

Another object of the invention is to provide an improved means for adjusting circuit breaker auxiliary switches.

The novel features that are considered characteristic of the invention are set forth in particular in the appended claims. The invention itself, however, both as to structure and operation, together with additional objects and advantages thereof, will be best understood from the following detailed description thereof when read in conjunction with the accompanying drawings, in which:

Figure 1 is a vertical sectional View of a circuit breaker to which the invention is applied.

Fig. 2 is an enlarged plan view of a portion of the circuit breaker shown in Fig. l with the cover removed to show the auxiliary switches.

Fig. 3 is a sectional view taken on line IIIIII of Fig. 2 looking in the direction of the arrows and showing one of the auxiliary switch mechanisms.

Fig. 4 is a detail view partly in section of one of the auxiliary switches.

Fig. 5 is a vertical sectional view of a part of the breaker showing the operating mechanism.

Fig. 6 is a vertical sectional view taken on line VI-VI of Fig. 2 showing one of the auxiliary switches.

Fig. '7 is a sectional view taken on line VII-VII of Fig. 4 and looking in the direction of the arrows.

Referring to Figure 1 of the drawings, the three-pole circuit breaker comprises, generally, a base 1 of molded insulating material, a cover 9 also of insulating material suitably secured to the base, operating mechanism l3, and a trip device indicated generally at IS. The casing formed by the base 1 and cover 9 is divided into three longitudinally extending compartments formed by the side walls of the casing and partition walls I4 molded integral with the base 1, and corresponding partition walls l6 molded integral with the cover 9 and cooperating with the partition walls I4. Each of the compartments is adapted to receive a stationary contact l8 and a cooperating movable contact 20 which, with corresponding terminals and connecting conductors, collectively form the three poles of the breaker. Each pole of the breaker is provided with end terminals disposed in suitable openings formed in the base 1 at each end thereof.

The respective stationary contacts |8, one for each pole of the breaker, are mounted on the lower end of a conductor 2| secured, by means of a screw 23, to the base 1. At its upper end the conductor 2| is connected by means of a bolt 25 to the terminal H.

The movable contact structures for the several poles are the same, for which reason only the one for the center pole will be described. The movable contact 20 for the center pole is secured to a contact arm 21 which is loosely supported on a channel-shaped switch-arm frame 29. The three channel-shaped frames are rigidly fastened for unitary movement by means of a metal tie bar 3| encased in an insulating tube 35 and extending across all of the poles of the breaker. The tie bar 3| is secured to the frames 29 by means of clamps 33. The channel-shaped frame 29 of the center pole is pivotally supported on a pin 31 mounted in a U-shaped main frame 39 secured by means of screws 4| to the base I. The pivot pin 31 forms the common pivot for the three mechanically connected switch arms or frames 29.

Each of the contact arms 21, to which the movable contacts 20 are secured, is attached to its corresponding channel-shaped frame 29 by means of a headed adjusting bolt 43, threadedly engaging the channel member and locked in adjusted position by lock nuts 45. The head of the bolt 43 loosely engages an inwardly extending flange or a sleeve (not shown) rigidly secured in a recess in the contact arm 2]. A cup-shaped spring retainer 5i disposed in an opening near the upper end of the channel member 29 receives one end of a compression spring 53 having its other end engaging the contact arm 21. The spring 53, in theopen-contact position of the breaker, biases the contact arm 2'! counterclockwise about the head of the bolt 53, the movement being limited by a tail portion 52 of the contact arm engaging the channel member 25% In the closed position, the spring 53 provides contact pressure. I

A flexible conductor 59 is electrically and mechanically connected to the lower end of the contact arm by means of a clamp SI of magnetic material and a rivet (not'shown). The lower end of the flexible conductor 59 is connected to a conductor 65 (Fig. 1) which, in turn, is connected by means of a bolt alto the lower terminal I! completing the circuit through the center pole of the breaker. The circuitsfor' the two outer poles are the same as the circuit for the center pole, for which reason, only the circui-t for the center pole will be traced. This c'lr cuit extends from the upper terminal ll through the bolt 25, conductor 2|, stationary and movable contacts [8-40, contact arm 2l,'fleXible conductor 5. 2, conductor 55 and bolt 5? to the lower terminal ll. v When the channel member 29 moves in coun terclockwise or closing direction, the arcing upper portions of the movable contacts are the first to touch the stationary contacts I8. Thereafter,

as the closing movement continues, the head of the bolt 33 engages the insert in the contact arm and causes the contact arm 2'! to rotate clock wise about the point of engagement of the insert with the head of the bolt '43. During the latter .part of this movement of the contact arm, the face portions of the movable contacts :26 are brought into parallel engagement with the stationary contacts l8 and the arcing portion of the movable contacts thereafterdisengage' the stationary contacts. 7 g

The movable contact structure comprising the channel-shaped'member 29, the tie bar'tl and the contact arms 2'! for all of the poles of the breaker, is, adapted to be operated to open and close positions by the common operating mecha-- nism [3 (Figs. 1 to 5). This operating mechanism comprises a releasable carrier or support member 69 pivotally mounted for movement with a shaft H mounted in the main frame 39, a pair of toggle links 73 and T5 in interconnecting the carrier 69 and the center-pole switch arm 29', a U-shaped operating lever ll, overcenter springs 19 for connecting the operating lever T! to the knee pivot pin 8| of the toggle 'l3l5, and an insulating operating handle 83 for the operating lever.

,' The toggle link 13 is pivotally connected by means of a pin 85 to the carrierfi and the toggle link 15 is pivotallyconnected by means'of a pin 81 to the channel-shaped frame 29 for the center pole of the breaker. The two legs of the operat: ing lever H are disposed adjacent the inner sides of the main frame members and are pivotally supported on pins 89 projecting inwardly from said frame members. The operating handle 83 projects through a slot 9! in the cover 9 and has an arcuate protective portion 53 and side plates 95 integral with the portion 93. The side plates 95 straddle the main frame 39and are secured to the two legs of the operating lever IT by means provision of novel auxiliary switch means and of screws 91 (only one being shown in Fig. 5) which threadedly engage the respective legs of the operating lever. The connectin portion of the operating lever is provided with a formed over portion llll. The portion iEi is for the purpose of engaging the resetting the carrier 59 to its latched position by movement of the operating handle as far as it will go in opening direction, in order to reset the trip mechanism following a tripping operation of the breaker. The carrier 59 is normally held in latched position as shown in Figs. 1 and 5 by a latch 35 of the trip device 15, which engages the latch portion lt'l of the carrier.

The operation of the circuit breaker operating mechanism is described as follows: with the parts in the position shown in Fig. l, with the contact means of all three poles of the breaker closed and the carrier 59 in latched up position; if the operating handle 83 is moved from the position shown in a clockwise direction to the opposite end of the slot ti to rotate th operating lever i'a' in a clockwise direction, the overcenter springs 59 will snap over center below the center line til-S5 and cause the toggle links l3l5 to collapse thereby causing simultaneous movement of all or" the channelframes and the mo able contacts to the open-circuit position with a snap action. To reclose the breaker, the operating handle is moved in the opposite direction back to the Fig. 1 position which movement causes the overcenter springs to snap over in the 0ppo'site direction moving the toggle to the in-toggle position thereby simultaneously closing all of the contact means with a snap action. The circuit breaker is opened automatically in response to overload currents occurring in any pole of the breaker, by operation or" the trip device ie. The trip device may be of any suitable. type, preferably of the type disclosed in copending application, Serial No. 513,868, filed December 11, 1943, by G. G. Grissinger, J. Sandin and Ture Lindstrom, and assigned to the assignee of the instant invention. Such trip devices are provided with thermally-responsive means operable "to release the latch after a time delay in response to overload currentsbelow a predetermined value and are also provided with electroresponsive means operable to instantaneously release the latch in response to overload currents above the predetermined value, or in response to short circuits.

When the latch N55 is released by the trip device, it frees the carrier 55) and permits the overcenter springs 15 to rotate the carrier in a ,counterclockwise direction about the pivot H, thus causing collapse of the" toggle it-l5 and opening of the contact means. The breaker cannot be reclosed until'the operating handle has been moved to the full open position in order to reset and relatch the carrier 59 with the latch 155. After the carrier has been relatched, the operating handle may be moved to its closed position to efiect closing of the contacts.

An important feature of the invention is the operating fmechanism therefor. One auxiliary switch means, herein referred'to as the bell alarm switch is operated only when the circuit breaker is automatically opened by operation of the'trip device in response to overload currents and another auxiliary switch means is operated in response to movement of the'main contacts each time the breaker is opened either manually or automatically."

.posite side of the contacts I2I Referring to Figs. 2 and 6 of the drawings, the trip device I is mounted on a base I09 which is removably mounted on the base I of the circuit breaker. The bell alarm switch indicated generally at III is mounted on a bracket H3 rigidly vice base I59. Similarly the main contact responsive auxiliary switch, indicated generally at H5, is mounted on a bracket II I also rigidly secured to the trip device base I09.

Both of the auxiliary switches III and H5 are mounted by identical means comprising threaded inserts HS symmetrically positioned on opposite sides of the center line of the circuit breaker, so that another auxiliary switch responsive to contact movement similar to switch H5 may be substituted for the bell alarm switch III if desired. Both the bell alarm switch and the other auxiliary switch are removable with the trip device without making any disconnection of the switches from their respective operating means as will be described hereinafter.

Since the structure of the bell alarm switch and the auxiliary switch is the same, only one, the bell alarm switch, will be described in detail and the same reference numerals will be applied to like parts. The bell alarm switch III (Fig. 2) comprises two or more terminal blocks III! of insulating material assembled between end frames I2I also of insulating material. The terminal blocks and frames are secured to the bracket H3 by means of screws I23 extending through suitable openings in the brackets H3 to Hi, the end frames I2I, the terminal blocks II 9 and threadedly engage brackets I25 of insulating material. Each of the terminal blocks H9 have molded therein a pair of terminal contact members I27 (only one of each pair being shown for each block H8) provided with a terminal connection I29 (Fig. 4) for connecting the switch in the circuit to be controlled thereby. A slide member I3I of molded insulating material is mounted for sliding movement in openings in the end frames I'2I and is biased by springs I33 to the position shown in Fig. 2. The slide I3I is provided with a projection I35 which limits its sliding movement in both directions by striking the end frames I 2|.

The slide I3I carries spring biased bridging contact members I3'I and I39 for bridging the pairs of contacts I2I. The bridging contact I3! is mounted on a rod I38 (Fig. '7) which extends upwardly through an opening in a bracket I40 secured to the slide I3I and has a cup-shaped spring retainer I42 secured to the upper end thereof. A spring I44 compressed between the retainer I42 and a similar spring retainer I46 secured to the bracket I45 biases the bridging contact I3l' toward the fixed contact members I21 and provides contact pressure when the slide I3I is moved upward to engage the contacts I3I with the upper pair of contact members I21. The bridging contact I 39 is similarly mounted with the exception that it is mounted above the 00- operating fixed contacts I2! to engage the lower pair of contacts I'2I when the slide I Si is moved downward. It will be noted that with the slide I3I in the position shown in Figs. i and 7, the contacts I3I-I2! are closed and the contacts I39--I2I are open so that upon downward movement of the slide I3I, the contacts I 38-42? will close and the contacts I3I-l2! will open. By assembling the bridging contacts I3! and I39 reversed and on the opthe contacts will and then disposed secured by means of screws H4 to the trip de- 6 operate in reverse, that is, contacts I3I-I21 will be normally open and will close upon operation of the slide I3I and contacts I 39-I2I will be normally closed and will open upon operation of the slide I3I.

The slide I3I of the bell alarm switch I II (Figs. 2 and 6) is operated by the operating mechanism of the breaker only when it is operated in response to overload currents. It was previously described how the releasable member or carrier 59 is rotated in a counterclockwise direction when released by operation of the trip device I5. The carrier 69 is secured to the shaft II which rotates therewith when the carrier is released. The shaft II extends beyond the right-hand main frame member 39 (Fig. 2) and has secured thereto a cam member MI. The cam member I 4I is provided with a groove in which is seated one end I43 of a torsion spring I coiled about a stud I47 mounted in the bracket I25. The other end i l? of the spring I45 bears against the upper end of the slide I3I and also engages a stop I50 on the bracket I25.

Referring to Fig. 6, when the carrier 69 is released and rotates in a counterclockwise direction, the cam member i ll rotates therewith in the same direction. During this movement, the cam I4I acts to rotate the end I43 of the spring I45 in a counterclockwise direction about the stud I47 which movement, due to the engagement of the end I45 of the spring 545 with the slide I3I, biases and moves the slide downward against the tension of the springs I33 to operate the contacts I3i and I39 in the manner set forth above.

When the carrier 59 is rotated clockwise by movement of the handle 83 to the ofi position in order to relatch it with the latch I 05, the cam member MI is rotated therewith thereby permitting clockwise movement of the spring I45. The slide :3! and the spring I45 are then returned to their normal positions as shown in Fig. 6 by the springs I33.

The spring I45 may be adjusted relative to the slide I3I and the cam MI by rotation of an eccentric sleeve I5I mounted on the stud I4! within the coil of the spring I45.

The construction of the auxiliary switch H5 is the same as that of the bell alarm switch with the exception that a spring I53 supported on the eccentric sleeve ISI for the auxiliary switch has one end I extended (Fig. 3) to be engaged and operated directly by the channel-shaped frame 29 for the left-hand pole (Fig. 2) of the breaker. The other end I51 of the spring I53 is adapted to engage and operate the slide I3I for the auxiliary switch H5.

Referring to Fig. 3 of the drawings, it will be seen that the end I52 of the spring I53 normally rests against a stop I58 and the bracket I25 and the end I55 of the spring I53 is disposed to be engaged by the channel-shaped frame 29 of the movable contact structure. The end I5! of the spring is disposed to engage the upper end of the slide I3I.

When the main movable contact structure is operated to the open position, shown in dot and dash lines in Fig. 3, it operates the spring I53 in a clockwise direction and the end I51 of the spring moves the slide I3I downward to actuate the contacts I3I--I2I and I39I2I of the auxiliary switch. When the main movable contact structure is operated to closed position the channel-shaped frame 29 frees the spring I53 and perauxiliary .iary switch, said auxiliary switch of the trip device which is removably mounted in the breaker. The switch operating springs Hi and 553 merely press against the cam member l4! and the channel member 29 respectively thus permitting removal of the switches H l and H5 without the necessity of disengaging any connection with the mechanism which operates them. The movable contacts of both the bell alarm switch and the auxiliary switch are mounted on insulating slides thereby eliminating the necessity of insulating links and connections.

While the invention has been disclosed in accordance with prcvisionsoi the patent statutes, it is to be understood that various changes in the structural details thereof may be made without departing from some of the essential features of the invention.

We claim as our invention:

1. In a circuit breaker comprising relatively movable contact means and operating means releasable to cause automatic opening of said contact means, a trip device removably mounted in said breaker and operable to release said operating means, an auxiliary switch means mounted on said trip device and removable from thebreaker ti erewith, spring means mounted on said switch, said spring means being .directly engageable by said movable contact means upon movement thereof to actuate said auxiliary switch. 1

2. In a circuit breaker comprising relatively movable contact means and operating mechanism releasable to cause opening or" said contact means, .a trip said spring means .to actuate said auxiliary switch.

.3. In a circuit breaker comprising relatively means operable by I in said breaker and operable to cause automatic opening of said contact means, a plurality of auxiliary switch means mounted on said trip device, means comprising a spring operable by said movable contact means whenever said contact means moves to open position to actuate one of said auxiliary switch means, and a second spring operable by said operating means only on automatic opening operation to actuate another of said auxiliary switch means.

'5. In a circuit breaker comprising relatively movable contact means and operating means therefor, manual means for operating said operating means to efiect opening and closing of said contact means, a trip device removably mounted in said breaker and operable to cause automatic opening of said contact means, a plurality of auxiliary switch means mounted on said trip device, means comprising a spring operable by said movable contact means whenever said contact means moves to open position to actuate one of said auxiliary switch means, and a second spring operable by said operating means only on automatic opening operation to actuate another of said auxiliary switch means, and said trip device, said auxiliary switch means and said spring means being removable from said breaker as a unit.

6. In a circuit breaker comprising relatively movable contact means and operating means therefor, manual means for operating said operating means to effect opening and closing of said contact means, a trip device operable to cause automatic opening of said contact means, a plurality of auxiliary switch means, one of said auxiliary switch means being operable by said movable contact means whenever said contact means moves to open position, and the other of said auxiliary switch means being operable by said 0 operating means only on automatic opening oper- .device removably mounted in said breaker and operable to cause release of said operating movable contact means and operating mocha-"'5 nism releasable to cause opening of said contact means, a trip device removably mounted in said breaker and operable to cause release of said operating mechanism,

by said releasable operating mechanism for ento actuate said auxilmeans, said spring means and said trip device being removahis as a unit from said breaker without disengaging any connection with said operating mechanism.

a. In a circuit breaker comprising relatively movable contact means and operating means therefor, manual means for operating said operating means to effect opening and closing of said contact means, a trip device removably mounted gaging said spring means ,an. auxiliary switch means mounted on said trip device and removable from ation, and both of said auxiliary switch means being mounted by identical but oppositely positioned mounting means on said trip device.

'7. In a circuit breaker comprising relatively movable contact means and operating mechanism therefor, a releasable member operable when released to cause automatic opening of said contact means, a trip device removably mounted in said breaker and operable to release said releasable member, an auxiliary switch device mounted on said trip device and removable therewith from said breaker, means comprising a torsion spring mounted on said auxiliary switch device for actuating said auxiliary switch, means comprising a part movable with said releasable member and operabl upon release of said releasable member to engage and actuate said torsion spring, said torsion spring being removable from the breaker with said auxiliary switch device without disengaging any connection with said part.

8. In a circuit breaker comprising relatively movable contact means and operating mechanism therefor, a releasable member operable when released to cause automatic opening of said contact means, a trip device removably mounted in said breaker and operable to release said releasable member, an auxiliary switch device mounted on said trip device and removable therewith from ,said breaker, means comprising a torsion spring 9 with said auxiliary switch device without disengaging any connection with said part and operating means for adjusting said torsion spring relative to said auxiliary switch and said part.

9. In a circuit breaker comprising relatively movable contact means and operating mechanism therefor, a releasable member operable when released to cause automatic opening of said contact means, a trip device removably mounted in said breaker and operable to release said releasable member, an auxiliary switch device mounted on said trip device and removable therewith from said breaker, means comprising a torsion spring mounted on said auxiliary switch device for actuating said auxiliary switch, means comprising apart movable with said releasable member and operable upon release of said releasable member to engage and actuate said torsion spring, said torsion spring being removable from the breaker with said auxiliary switch device without disen-. gaging any connection with said part and means comprising an eccentric sleeve operable to adjust the position of said torsion spring.

10. In a circuit breaker comprising relatively movable contacts, a switch arm operable to open and close said contacts, a trip device removably mounted in said breaker and operable to cause opening movement of said switch arm, an auxiliary switch mounted on said trip device and removable therewith from said breaker, means comprising a torsion spring having one end operatively related to said auxiliary switch, the other end of said torsion spring being directly engageable by said switch arm when said switch arm moves to open said contacts to operate said auxiliary switch.

11. In a circuit breaker comprising relatively movable contact means and operating means therefor including a member releasable to cause automatic opening of said contact means, a trip device operable to cause release of said releasable member, auxiliary switch means, a pivot on said auxiliary switch means, means comprising a torsion spring rotatably mounted on said pivot and having one end operatively related to said auxiliary switch means, means movable with said releasable member oper'atively related to the other end of said torsion spring, said movable means when released rotating said torsion spring about said pivot to actuate said auxiliary switch means, and adjusting means on said pivot for adjusting said torsion spring relative to said movable memher and said auxiliary switch means.

12. In a circuit breaker comprising relatively movable contact means and operating means therefor including a member releasable to cause automatic opening of said contact means, a trip device operable to cause release of said releasable member, auxiliary switch means, means comprising a torsion spring having one end operatively related to said auxiliary switch means, means movable with said releasable member operatively related to the other end of said torsion spring, and said movable means when released operating said torsion spring to actuate said auxiliary switch means and means for adjusting the position of said torsion spring relative to said auxiliary switch means and said movable member.

13. In a circuit breaker comprising relatively movable contact means and operating means therefor including a member releasable to cause automatic opening of said contact means, a pivot for supporting said releasable member, a trip device operable to cause release of said pivoted member, auxiliary switch means, a torsion spring having one end operatively related to said auxiliary switch means, eccentric means on said auxiliary switch means mounting said torsion spring for rotary movement, means on said pivot engaging the other end of said torsion spring and operable upon release of said releasable member to operate said spring to actuate said auxiliary switch means, and adjusting means for adjusting said eccentric means to vary the position of said torsion spring.

14. In a circuit breaker comprising relatively movable contact means and operating means therefor including a pivoted member releasable to cause automatic opening of said contact means, a pivot for supporting said releasable member, a trip device operable to cause release of said pivoted member, auxiliary switch means, means comprising a spring having one end abutting against said auxiliary switch means, means mounting said spring for rotary movement, a lateral extension on said pivot, and cam mean on said extension engaging the other end of said spring and operable upon release of said releasable member to rotate said spring about said mounting means to actuate said auxiliary switch means.

15. In a circuit breaker comprising relatively movable contact means, a switch arm operable to open and close said contact means, operating means comprising a member releasable to cause automatic opening movement of said switch arm, a pivot for pivotally supporting said releasable member, a trip device removably mounted in said circuit breaker and operable to cause release of said releasable member, auxiliary switch means comprising a plurality of auxiliary switches mounted on said trip device, a first torsion spring having one end associated with one of said auxiliary switches the other end of said torsion spring being directly engageable by said switch arm for operating said one auxiliary switch in response to movement of said switch arm, a second torsion spring having one end associated with another of said auxiliary switches, means on said pivot engaging the other end of said second torsion spring and operable upon releas of said releasable member for operating said second torsion spring to actuate said other auxiliary switch in response to movement of said releasable member.

16. In a circuit breaker comprising relatively movable contact means, a switch arm operable to open and close said contact means, operating means comprising a member releasable to cause automatic opening movement of said switch arm, a pivot for pivotally supporting said releasable member, a trip device removably mounted in said circuit breaker and operable to cause release of said releasable member, auxiliary switch means comprising a plurality of auxiliary switches mounted on said trip device, a first torsion spring having one end associated with one of said auxiliary switches th other end of said torsion spring being directly engageable by said switch arm for operating said one auxiliary switch in response to movement of said switch arm, a second torsion spring having one end associated with another of said auxiliary switches, means on said pivot engaging the other end of said second torsion spring and operable in response to movement of said releasable member for operating said second torsion spring to actuate said other auxiliary switch, said auxiliary switch means and said tortion spring being removable from the breaker with said trip device without disengaging any connections with said switch arm or said releasable member.

means, auxiliary switch meansmounted on said 5 trip device; and rmo'vzibie therewith from said breaker", actuatin inealns f-o'r'said auxiliary switch means comprising a; torsion spring mounted on solid auxiliary switch device, means comprising a portion of said operating means for engaging and actuating said torsion spring, and said torsion sprin being removable with said auxiliary switch device without disengaging any connection with said norti'on of Said operating means.

JEROME SANDIN. RICHARD HAUSER.

12 REFERENCES CITED The following references are of record in the file of this patent:

STATES PATENTS Number Name Date 455,837 Dahlgren July 14, 1891 8271181 Richardson July 31, 1906 21159385 Frank et a] Nov. 3, 1936 

